7-Zip is a

free and open-source Free and open-source software (FOSS) is software available under a Software license, license that grants users the right to use, modify, and distribute the software modified or not to everyone free of charge. FOSS is an inclusive umbrella term ...

file archiver In computing, a file archiver is utility software that combines computer file, files into a single archive file or in less common cases, multiple files. A minimally designed archiver might concatenate the content of files along with file file n ...

, a utility used to place groups of files within compressed containers known as "archives". It is developed by Igor Pavlov and was first released in 1999. 7-Zip has its own

archive format In computing, an archive file stores the content of one or more computer file, files, possibly lossless compression, compressed, with associated metadata such as file name, directory structure, error detection and correction information, commentary ...

called 7z introduced in 2001, but can read and write several others. The program can be used from a Windows

graphical user interface A graphical user interface, or GUI, is a form of user interface that allows user (computing), users to human–computer interaction, interact with electronic devices through Graphics, graphical icon (computing), icons and visual indicators such ...

that also features shell integration, or from a

command-line interface A command-line interface (CLI) is a means of interacting with software via command (computing), commands each formatted as a line of text. Command-line interfaces emerged in the mid-1960s, on computer terminals, as an interactive and more user ...

as the command 7z that offers

cross-platform Within computing, cross-platform software (also called multi-platform software, platform-agnostic software, or platform-independent software) is computer software that is designed to work in several Computing platform, computing platforms. Some ...

support (see

versions Version may refer to: Computing * Software version, a set of numbers that identify a unique evolution of a computer program * VERSION (CONFIG.SYS directive), a configuration directive in FreeDOS Music * Cover version * Dub version * Remix * Versi ...

for details). An obsolete port of 7-Zip to

POSIX The Portable Operating System Interface (POSIX; ) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines application programming interfaces (APIs), along with comm ...

systems was called p7zip. Most of the 7-Zip

source code In computing, source code, or simply code or source, is a plain text computer program written in a programming language. A programmer writes the human readable source code to control the behavior of a computer. Since a computer, at base, only ...

is under the LGPL-2.1-or-later license; the unRAR code, however, is under the LGPL-2.1-or-later license with an "unRAR restriction", which states that developers are not permitted to use the code to reverse-engineer the RAR compression algorithm. Since version 21.01 alpha, Linux support has been added to the 7zip project.

Archive formats

7z

By default, 7-Zip creates 7z-format archives with a .7z

file extension File or filing may refer to: Mechanical tools and processes * File (tool), a tool used to remove fine amounts of material from a workpiece. ** Filing (metalworking), a material removal process in manufacturing ** Nail file, a tool used to gen ...

. Each archive can contain multiple directories and files. As a ''container'' format, security or size reduction are achieved by looking for similarities throughout the data using a stacked combination of filters. These can consist of pre-processors, compression algorithms, and

encryption In Cryptography law, cryptography, encryption (more specifically, Code, encoding) is the process of transforming information in a way that, ideally, only authorized parties can decode. This process converts the original representation of the inf ...

filters. The core 7z compression uses a variety of

algorithm In mathematics and computer science, an algorithm () is a finite sequence of Rigour#Mathematics, mathematically rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algo ...

s, the most common of which are

bzip2 bzip2 is a free and open-source file compression program that uses the Burrows–Wheeler algorithm. It only compresses single files and is not a file archiver. It relies on separate external utilities such as tar for tasks such as handli ...

, PPMd, LZMA2, and LZMA. Developed by Pavlov, LZMA is a relatively new system, making its debut as part of the 7z format. LZMA uses an LZ-based sliding dictionary of up to 3840 MB in size, backed by a range coder. The native 7z

file format A file format is a Computer standard, standard way that information is encoded for storage in a computer file. It specifies how bits are used to encode information in a digital storage medium. File formats may be either proprietary format, pr ...

is open and modular.

File name A filename or file name is a name used to uniquely identify a computer file in a file system. Different file systems impose different restrictions on filename lengths. A filename may (depending on the file system) include: * name – base ...

s are stored as

Unicode Unicode or ''The Unicode Standard'' or TUS is a character encoding standard maintained by the Unicode Consortium designed to support the use of text in all of the world's writing systems that can be digitized. Version 16.0 defines 154,998 Char ...

. In 2011,

TopTenReviews Future plc is a British publishing company. It was started in 1985 by Chris Anderson. It is listed on the London Stock Exchange and is a constituent of the FTSE 250 Index. History 1985–2012 The company was founded by Chris Anderson a ...

found that the 7z compression was at least 17% better than ZIP, and 7-Zip's own site has since 2002 reported that while compression ratio results are very dependent upon the data used for the tests, "Usually, 7-Zip compresses to 7z format 30–70% better than to zip format, and 7-Zip compresses to zip format 2–10% better than most other zip-compatible programs." The 7z file format specification is distributed with the program's source code, in the "doc" sub-directory.

Others

7-Zip supports a number of other compression and non-compression archive formats (both for packing and unpacking), including ZIP,

gzip gzip is a file format and a software application used for file compression and decompression. The program was created by Jean-loup Gailly and Mark Adler as a free software replacement for the compress program used in early Unix systems, and ...

, xz,

tar Tar is a dark brown or black viscous liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat. "a dark brown or black b ...

, and WIM. The utility also supports unpacking

APM APM, apm, or Apm may refer to: Technology Computer technology *Active policy management, a discipline within enterprise software *Advanced Power Management, a legacy technology in personal computers * Apple Partition Map, computer disk partiti ...

, ar, ARJ, chm,

cpio cpio is a general file archiver utility and its associated file format. It is primarily installed on Unix-like computer operating systems. The software utility was originally intended as a tape archiving program as part of the Programmer's Work ...

, deb, FLV, JAR, LHA/LZH, LZMA, MSLZ,

Office Open XML Office Open XML (also informally known as OOXML) is a zipped, XML-based file format developed by Microsoft for representing spreadsheets, charts, presentations and word processing documents. Ecma International standardized the initial version ...

, onepkg, RAR,

RPM Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or r⋅min−1) is a unit of rotational speed (or rotational frequency) for rotating machines. One revolution per minute is equivalent to hertz. Standards ISO 80000-3:2019 def ...

, smzip, SWF, XAR, and Z archives and cramfs,

DMG DMG may refer to: Organizations Entertainment * DMG Clearances, music licensor in Delaware, USA * DMG Entertainment, a Chinese-based film production and distribution company * DMG Nashville, a brand of Hollywood Records specializing in country musi ...

FAT In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food. The term often refers specif ...

HFS HFS may refer to: Businesses and organisations * Croatian Film Association () * Hellenic Fire Service, Greece * Hospitality Franchise Systems, US Computing * Hierarchical file system, a system for organizing directories and files * Hierarchica ...

ISO The International Organization for Standardization (ISO ; ; ) is an independent, non-governmental, international standard development organization composed of representatives from the national standards organizations of member countries. Me ...

, MBR,

NTFS NT File System (NTFS) (commonly called ''New Technology File System'') is a proprietary journaling file system developed by Microsoft in the 1990s. It was developed to overcome scalability, security and other limitations with File Allocation Tabl ...

SquashFS Squashfs is a compressed read-only file system for Linux. Squashfs compresses files, inodes and directories, and supports block sizes from 4 KiB up to 1 MiB for greater compression. Several compression algorithms are supported. Squashfs is ...

, UDF, and VHD

disk image A disk image is a snapshot of a storage device's content typically stored in a file on another storage device. Traditionally, a disk image was relatively large because it was a bit-by-bit copy of every storage location of a device (i.e. every ...

s. 7-Zip supports the ZIPX format for unpacking only. It has had this support since at least version 9.20, which was released in late 2010. 7-Zip added support for RAR5 in 2015. 7-Zip can open some MSI files, allowing access to the meta-files within along with the main contents. Some Microsoft CAB (

LZX LZX is an LZ77 family Data compression, compression algorithm, a slightly improved version of DEFLATE. imlib: the open source Windows Imaging (WIM) library - Compression algorithm https://wimlib.net/compression.htmlIt is also the name of a arc ...

compression) and NSIS (LZMA) installer formats can be opened. Similarly, some Microsoft executable programs (.

EXE Exe or EXE may refer to: * .exe, a file extension * exe., abbreviation for Executive (disambiguation)#Role, title, or function, executive Places * River Exe, in England * Exe Estuary, in England * Exe Island, in Exeter, England Transportation a ...

s) that are self-extracting archives or otherwise contain archived content (e.g., some setup files) may be opened as archives. When compressing ZIP or gzip files, 7-Zip uses its own DEFLATE encoder, which may achieve higher compression, but at lower speed, than the more common

zlib zlib ( or "zeta-lib", ) is a software library used for data compression as well as a data format. zlib was written by Jean-loup Gailly and Mark Adler and is an abstraction of the DEFLATE compression algorithm used in their gzip file compre ...

DEFLATE implementation. The 7-Zip deflate encoder implementation is available separately as part of the AdvanceCOMP suite of tools. The decompression engine for RAR archives was developed using freely available source code of the unRAR program, which has a licensing restriction against creation of a RAR compressor. 7-Zip v15.06 and later support extraction of files in the RAR5 format. Some

backup In information technology, a backup, or data backup is a copy of computer data taken and stored elsewhere so that it may be used to restore the original after a data loss event. The verb form, referring to the process of doing so, is "wikt:back ...

systems use formats supported by archiving programs such as 7-Zip; e.g., some Android backups are in tar format, and can be extracted by archivers such as 7-Zip. Some forks add more formats.

File manager

7-Zip comes with a file manager along with the standard archiver tools. The file manager has a toolbar with options to create an archive, extract an archive, test an archive to detect errors, copy, move, and delete files, and open a file properties menu exclusive to 7-Zip. The file manager, by default, displays hidden files because it does not follow

Windows Explorer File Explorer, previously known as Windows Explorer, is a file manager application and default desktop environment that is included with releases of the Microsoft Windows operating system from Windows 95 onwards. It provides a graphical user i ...

's policies. The tabs show name, modification time, original and compressed sizes, attributes, and comments (

4DOS 4DOS is a command-line interpreter by JP Software, designed to replace the default command interpreter COMMAND.COM in MS-DOS and Windows. It was written by Rex C. Conn and Tom Rawson and first released in 1989. Compared to the default, it has ...

descript.ion format). When going up one directory on the root, all drives, removable or internal appear. Going up again shows a list with four options: * Computer: loads the drives list * Documents: loads user's documents, usually at %UserProfile%\My Documents * Network: loads a list of all network clients connected * \\.: Same as "Computer" except loads the drives in low-level filesystem access. This results in critical drive files and deleted files still existing on the drive to appear. (NOTE: As of November 2020, access to the active partition in low-level mode is not allowed for currently unknown reasons.)

Features

7-Zip supports: * 32 and 64-bit x86, ARM64 architecture * File Manager * Encryption via the 256-bit AES cipher, which can be enabled for both files and the 7z hierarchy. When the hierarchy is encrypted, users are required to supply a

password A password, sometimes called a passcode, is secret data, typically a string of characters, usually used to confirm a user's identity. Traditionally, passwords were expected to be memorized, but the large number of password-protected services t ...

to see the filenames contained within the archive. WinZip-developed Zip file AES encryption standard is also available in 7-Zip to encrypt ZIP archives with AES 256-bit, but it does not offer filename encryption as in 7z archives. * Volumes of dynamically variable sizes, allowing use for backups on removable media such as writable CDs and DVDs * Usability as a basic orthodox file manager when used in dual panel mode * Multiple-core CPU threading * Opening EXE files as archives, allowing the decompression of data from inside many "Setup" or "Installer" or "Extract" type programs without having to launch them * Unpacking archives with corrupted filenames, renaming the files as required * Create self-extracting single-volume archives * Command-line interface * Graphical user interface. The Windows version comes with its own GUI. For various

Unix-like A Unix-like (sometimes referred to as UN*X, *nix or *NIX) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Uni ...

systems, several GUIs, e.g. PeaZip, can handle the 7z file format based on the Unix binaries. * Calculating

checksum A checksum is a small-sized block of data derived from another block of digital data for the purpose of detecting errors that may have been introduced during its transmission or storage. By themselves, checksums are often used to verify dat ...

s in the formats CRC-32, CRC-64, SHA-1, or SHA-256 for files on disk, available either via command line or Explorer's context menu * Available in 89 languages * Ability to optionally record creation dates (tc) and last access dates (ta) in archives (in addition to modification dates).

Versions

Three

command-line A command-line interface (CLI) is a means of interacting with software via commands each formatted as a line of text. Command-line interfaces emerged in the mid-1960s, on computer terminals, as an interactive and more user-friendly alternativ ...

versions are provided: 7z (7z.exe), using external libraries to support a large number of different formats and the ability to support even more formats via plug-ins; 7za (7za.exe), which is a standalone executable containing built-in modules, but with compression/decompression support limited to 7z, ZIP,

, Z and

formats; and 7zr (7zr.exe), which is a ''minimized'' standalone executable with compression/decompression support limited to just the 7z format. A 64-bit version is available, with support for large memory maps, leading to faster compression. All versions support multi-threading.

Forks

* p7zip is a deprecated port of 7-Zip to

operating systems (including

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

FreeBSD FreeBSD is a free-software Unix-like operating system descended from the Berkeley Software Distribution (BSD). The first version was released in 1993 developed from 386BSD, one of the first fully functional and free Unix clones on affordable ...

, and

macOS macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...

FreeDOS FreeDOS (formerly PD-DOS) is a free software operating system for IBM PC compatible computers. It intends to provide a complete MS-DOS-compatible environment for running Legacy system, legacy software and supporting embedded systems. FreeDOS ca ...

OpenVMS OpenVMS, often referred to as just VMS, is a multi-user, multiprocessing and virtual memory-based operating system. It is designed to support time-sharing, batch processing, transaction processing and workstation applications. Customers using Op ...

AmigaOS 4 AmigaOS 4 (abbreviated as OS4 or AOS4) is a line of Amiga operating systems which runs on PowerPC microprocessors. It is mainly based on AmigaOS 3.1 source code developed by Commodore International, Commodore, and partially on version 3.9 develop ...

, and

MorphOS MorphOS is an AmigaOS-like operating system designed for Power and PowerPC based computers. The core, based on the Quark microkernel, is proprietary, although several libraries and other parts are open source, such as the Ambient desktop. The p ...

. Since support for

operating systems has officially been added to upstream 7-Zip in version 21.01, the ''p7zip'' fork has become obsolete and is no longer updated; the last available version of ''p7zip'' is 16.02. ** In most Linux distributions, the command p7zip is now merely a wrapper that calls the standard 7za or 7zr program. * 7-zip ZS is a fork with

Zstandard Zstandard is a lossless compression, lossless data compression algorithm developed by Yann Collet at Facebook. Zstd is the corresponding reference implementation in C (programming language), C, released as open-source software on 31 August 201 ...

and various other compression algorithms added to the file format. ** p7zip-zstd (p7zip with zstd) is p7zip with ZS additions. * NanaZip is a fork integrating changes from many sources, modernized for the

Microsoft Store The Microsoft Store (formerly known as the Windows Store) is a digital distribution platform operated by Microsoft. It was created as an app store for Windows 8 as the primary means of distributing Universal Windows Platform apps. With ...

Plugins

7-zip comes with a plug-in system for expansion. The official "Links" page points to many plugins written by TC4Shell, providing extra file support.

Software development kit

7-Zip has a LZMA SDK which was originally dual-licensed under both the GNU LGPL and Common Public License, with an additional special exception for linked binaries. On 2 December 2008, the SDK was placed by Igor Pavlov in the

public domain The public domain (PD) consists of all the creative work to which no Exclusive exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly Waiver, waived, or may be inapplicable. Because no one holds ...

Security

On older versions, self-extracting archives were vulnerable to

arbitrary code execution In computer security, arbitrary code execution (ACE) is an attacker's ability to run any commands or code of the attacker's choice on a target machine or in a target process. An arbitrary code execution vulnerability is a security flaw in softwa ...

through DLL hijacking: they load and run a DLL named UXTheme.dll, if it is in the same folder as the executable file. 7-Zip 16.03 Release notes say that the installer and SFX modules have added protection against DLL preloading attack. Versions of 7-Zip prior to 18.05 contain an

vulnerability in the module for extracting files from RAR archives (), a vulnerability that was fixed on 30 April 2018. Versions prior to 23.0 also contained an

vulnerability, fixed on 7 May 2023. A year later, a severe remote code execution vulnerability was found on versions prior to 24.07 (), it was fixed on 20 November 2024.

Reception and usage

Snapfiles.com in 2012 rated 7-Zip 4.5 stars out of 5, noting, " tsinterface and additional features are fairly basic, but the compression ratio is outstanding". On

TechRepublic TechRepublic is an online trade publication and social community for IT professionals, providing advice on best practices and tools for the needs of IT decision-makers. It was founded in 1997 in Louisville, Kentucky, by Tom Cottingham and Kim S ...

in 2009, Justin James found the detailed settings for Windows File Manager integration were "appreciated" and called the compression-decompression benchmark utility "neat". And though the archive dialog has settings that "will confound most users", he concluded: "7-Zip fits a nice niche in between the built-in Windows capabilities and the features of the paid products, and it is able to handle a large variety of file formats in the process." Between 2002 and 2024, 7-Zip was downloaded 428 million times from

SourceForge SourceForge is a web service founded by Geoffrey B. Jeffery, Tim Perdue, and Drew Streib in November 1999. SourceForge provides a centralized software discovery platform, including an online platform for managing and hosting open-source soft ...

alone. The software has received awards, In 2007, SourceForge granted it community choice awards for "Technical Design" and for "Best Project". In 2013,

Tom's Hardware ''Tom's Hardware'' is an online publication owned by Future plc and focused on technology. It was founded in 1996 by Thomas Pabst. It provides articles, news, price comparisons, videos and reviews on computer hardware and high technology. The s ...

conducted a compression speed test comparing 7-ZIP, MagicRAR,

WinRAR WinRAR is a trialware file archiver utility, developed by Eugene Roshal of win.rar GmbH. It can create and view archives in RAR or ZIP file formats, and unpack numerous archive file formats. To enable the user to test the integrity of archive ...

, WinZip; they concluded that 7-ZIP beat out all the others with regards to compression speed, ratio, and size and awarded the software the 2013 Tom's Hardware Elite award.

References

External links

*
7-Zip Portable
at PortableApps.com {{FOSS 1999 software Cross-platform free software Disk image extractors File archivers Free data compression software Free file managers Free multilingual software Free software programmed in C Free software programmed in C++ Portable software Software using the GNU Lesser General Public License Windows compression software